SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66caa499421b3502739efb98f1f3818ba0ceabda3b23854e96f4b6cfd5edd176' 
  AND token = 'PyZ/UNZGjUllkVWbF8LC4gs5RRyDUV25MhsgNN+zsn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}